Conventionally, laminated ceramic capacitors are typically manufactured as follows.
First, ceramic green sheets with a predetermined conductive pattern formed on their surfaces are manufactured, and a predetermined number of the ceramic green sheets is then stacked, sandwiched between ceramic green sheets with no conductive pattern formed, and subjected to thermo-compression bonding to form a integrated ceramic laminate.
Next, this ceramic laminate is calcined, thereby obtaining a ceramic sintered body with internal electrodes buried therein. Then, external electrodes are formed on the outer surface of the ceramic sintered body, thereby manufacturing a laminated ceramic capacitor. It is to be noted that the external electrodes are formed by providing a conductive paste containing conductive metal powder and glass frit on the outer surface of the laminate and firing the conductive paste.
In addition, a high dielectric constant is required in this type of laminated ceramic capacitor, for the dielectric ceramic in order to achieve reduction in size and increase in capacitance. Therefore, BaTiO3-based materials have been widely used as the ceramic material.
The BaTiO3 is a ferroelectric, and large numbers of core-shell structures and the like have been found in which an additive is dispersed only in the vicinity of surface layers of the crystal grains in order to change various dielectric characteristics. On the other hand, some ceramic materials are nearly homogeneous in terms of composition and the crystal system throughout crystal grains, as described in Patent Document 1. The use of such a homogeneous structure relatively facilitates improvement in the dielectric constant.
Patent Document 1: Japanese Patent Application Laid-Open No. 11-273985